Help BSW27 Carburettor (GSXR250 / GSX250F) Slider Question

Hi all, first of all this forum is an awesome resource when it comes to info for BSW27 carburettors and GSXR250 / GSX250F engine information, I'm glad google helped me stumble across 2fiftycc.com!

For the last few years I've been the neglecting owner of an '87 GSXR250 (GJ72A), it never really ran all that well and never sounded too healthy.

Recently I decided to put some love back into the bike and dismantled the carburetor and cleaned out the pilot jets, main jets, and inspected the slider assembly. The slide holders were buggered and quite loose, but for some reason stuck solid with a 90 degree rotation, obviously not ideal in the long run but it works for the minute.

A few of the sliders also have chips in them, and appear to be damaged where the slide holder fits to them so I'd like to replace them too, while inspecting I noticed that the sliders all have a number printed on the top of them.

Both pairs of carbs I own seem to have a mix and match of them.
My spare carbs as seen in the pictures have 2x #1, 1x #3 & 1x #2
My carbs currently fitted to the bike have, 3x #4 & 1x #3

Does anyone know the relevance of the number on top of the slider?
I thought perhaps it might be a sizing difference,
or for matching which cylinder it belonged to when first assembled.

In the manual it simply states that the part number for the sliders is 13551-34A31, perhaps this is for a packet of 4x?

 

I spoke to a friend who's pretty well versed with engineering and he suggested the same, and it definitely makes sense.

Thanks for the response!